Fruit Flies

Mexican Fruit Fly Quarantine Issued in San Diego County

Brian German Pest Update

A Mexican fruit fly quarantine has been issued for a portion of San Diego County after the discovery of seven flies in the city of Encinitas.  The area under quarantine measures 65 square miles.

Mexican Fruit Fly


The United States Department of Agriculture, the California Department of Food and Agriculture (CDFA), and the San Diego County Agricultural Commissioner are combining their resources to release sterile male Mexican fruit flies as a means of eradication.  The release of 325,000 males per square mile each week will prevent the production of offspring, eventually eliminating the pest altogether.

The Mexican fruit fly can infest more than 50 types of host trees, including oranges, grapefruit, nectarines, and peaches.  San Diego County’s recently developed coffee crops are also susceptible to infestation.  There are approximately twelve nurseries and 30 farms in Encinitas that fall within the quarantine area.  All fruit vulnerable to infestation within the quarantine zone is required to be treated or processed before it can be sold.  Nurseries are also required to remove fruit from trees before selling them.

The quarantine’s northern border is McClellan Palomar Airport. The border on the south is San Dieguito Road.  The Pacific Ocean is the western border with the San Dieguito River on the east.  A map of the quarantine area can be found on the CDFA website.  The last quarantine prompted by Mexican fruit flies in the area consisted of 130 square miles in Valley Center in 2002.

Residents who believe they have fruits or vegetables that have become infested with fruit fly larvae are encouraged to call the state’s Pest Hotline at 1-800-491-1899.